Electrically conducting polymers are used in a variety of optoelectronics applications such as polymeric light emitting diodes for use in thin film displays, solid state lighting, organic photovolatics, advanced memory devices, organic field effect transistors, ultracapacitors and electroluminescent devices.
Polyacetylene was one of the first electrically conducting polymers to be extensively investigated and the discovery that polyacetylene exhibited useful electrical conductivity, particularly upon doping, created substantial interest in other types of electrically conducting polymers.
Conjugated poly(thiophenes) and substituted thiophene derivatives are also known to exhibit electrical conductivity. Such polymers can be cast into films and doped with conventional p- and n-type dopants or the doped polymers can be cast into films and their electrical properties modified accordingly. The resulting cast films are suitable for use in a variety of optoelectronic applications.
US 2004/0010115A1, a patent application from which the present continuation-in-part application claims priority, discloses homopolymers and copolymers comprising repeating units of thieno[3,4-b]thiophene for use in electroactive applications. Water-borne dispersions of such polymers and copolymers can be cast by conventional methods to provide uniform, thin films which possess utility in numerous electroactive applications including electrochromic displays, optically transparent electrodes and antistatic coatings.
U.S. Pat. No. 6,645,401 B2 discloses conjugated polymers of dithienothiophene (DTT) with vinylene or acetylene connecting groups for use in semiconductors and charge transport materials for incorporation into electrooptical and electronic devices including field effect transistors, photovoltaic, and sensor devices. Polymers containing DTT formed by electrochemical polymerization are known but demonstrate limited solubility in solvents suitable for use in preparing electrooptical and electronic devices and generally inadequate photovoltaic properties.
U.S. Pat. No. 6,585,914 B2 discloses fluorocarbon-functionalized and/or heterocyclic modified poly(thiophenes), in particular, α, ω-diperfluorohexylsexithiophene for use in forming films which behave as n-type semiconductors. These poly(thiophenes) also can be used to form thin film transistors with FET mobility.
U.S. Pat. No. 6,676,857 B2 discloses mono-, oligo- and polymers having polymerized units of 3-substituted-4-fluorothiophene as liquid crystal materials for use in semiconductors, charge transport materials, electrooptical field effect transistors, photovoltaic and sensor devices.
U.S. Pat. No. 6,695,978 B2 discloses mono-, oligo- and polymers of benzo[b]thiophene and bisbenzo[b]-thiophene and their use as semiconductors and as charge transport materials in electrooptical devices.
U.S. Pat. No. 6,709,808 B2 discloses image forming materials incorporating electrically conductive polymers based upon pyrrole-containing thiophene polymers and aniline containing polymers.
J. P. Ferraris and coworkers in Synthesis and Electronic Properties of Poly(2-phenyl-thieno[3,4-b]thiophene), Chem. Mater. 1999 11, 1957-1958, report a synthetic preparation of the referenced composition of matter and its electronic properties.
M. Pomerantz and coworker in Poly(2-decyl-thieno[3,4-b]thiophene): a New Soluble Low-Band Gap Conducting Polymer, Synthetic Materials 84 (1997) 243-244 disclose a soluble low-bandgap conducting polymer, poly(2-decyl-thieno[3,4-b]thiophene), and a process for preparing the polymer.